Display device with capacitive touch sensor with slit formed in a surface of a detecting electrode opposed to a scanning electrode to realize detection with high accuracy

ABSTRACT

An information input device including a touch panel configured to be provided with a touch sensor that detects a position at which a sensing object is brought close to a sensing surface. In this information input device, the touch sensor has a scanning electrode and a detecting electrode that is opposed to the scanning electrode with the intermediary of a dielectric substance, and is a capacitive sensor whose electrostatic capacitance changes if the sensing object is brought close to the detecting electrode. Furthermore, a slit is formed in a surface of the detecting electrode opposed to the scanning electrode.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.15/478,919 filed Apr. 4, 2017, which is a continuation of U.S. patentapplication Ser. No. 15/244,898 filed Aug. 23, 2016, now U.S. Pat. No.9,652,075 issued May 16, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/743,547 filed Jun. 18, 2015, now U.S. Pat. No.9,454,279 issued Sep. 27, 2016, which is a continuation of U.S. patentapplication Ser. No. 12/759,260 filed Apr. 13, 2010, now U.S. Pat. No.9,092,095 issued Jul. 28, 2015, the entireties of which are incorporatedherein by reference to the extent permitted by law. The presentapplication claims the benefit of priority to Japanese PatentApplication No. JP 2009-102319 filed on Apr. 20, 2009 in the JapanPatent Office, the entirety of which is incorporated by reference hereinto the extend permitted by law.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to information input devices and displaydevices, and particularly to an information input device and a displaydevice including a panel provided with a capacitive touch sensor fordetecting the position to which an object to be sensed is brought close.

2. Description of the Related Art

Display devices such as liquid crystal display devices and organic ELdisplay devices have advantages such as small thickness, light weight,and low power consumption. Therefore, these display devices arefrequently used in mobile-use electronic apparatus such as cellularphones and digital cameras.

As one kind of such display devices, the liquid crystal display devicehas a liquid crystal panel formed by enclosing a liquid crystal layerbetween a pair of substrates as a display panel. The liquid crystalpanel is e.g. a transmissive panel. Specifically, illuminating lightemitted from an illuminating unit such as a backlight provided on theback side of the liquid crystal panel is modulated by the liquid crystalpanel and passes through the liquid crystal panel. By the modulatedilluminating light, image displaying is carried out on the front side ofthe liquid crystal panel.

This liquid crystal panel is based on e.g. the active-matrix system andincludes a TFT array substrate over which plural thin film transistors(TFTs) functioning as pixel switching elements are formed. Furthermore,in this liquid crystal panel, a counter substrate is so disposed as tobe opposed to this TFT array substrate and the liquid crystal layer isprovided between the TFT array substrate and the counter substrate. Inthis liquid crystal panel of the active-matrix system, the pixelswitching element inputs potential to a pixel electrode to thereby applyvoltage to the liquid crystal layer and control the transmittance of thelight passing through the pixel. Thereby, the image displaying iscarried out.

For the above-described display device, a touch panel is often providedas an information input device on the display panel in order to allowthe user to input operation data by utilizing images such as iconsdisplayed on the screen of the display panel.

In addition to the display device in which the touch panel is providedas an external unit on the display panel, a display device in which thedisplay panel has a built-in touch panel function has also beenproposed.

For example, display panels provided with a capacitive touch sensor havebeen proposed (refer to e.g. Japanese Patent Laid-open Nos. 2008-9750,2009-3916, and 2008-129708).

In these display panels, the capacitive touch sensor is so configuredthat the electrostatic capacitance changes when an object to be sensed(also referred to as a sensing object) is brought close to the sensingsurface, and the position at which the sensing object is brought closeto the sensing surface is detected based on the change in theelectrostatic capacitance.

FIGS. 30A and 30B are diagrams showing the appearance when a capacitivetouch sensor TS is driven. FIG. 30A shows the case in which a sensingobject F is not brought close to the sensing surface of the touch sensorTS. On the other hand, FIG. 30B shows the case in which the sensingobject F is brought close to the sensing surface.

As shown in FIGS. 30A and 30B, for the capacitive touch sensor TS, forexample a pair of electrodes, i.e. a scanning electrode 23J and adetecting electrode 24J, are opposed to each other with the intermediaryof a dielectric substance Y, so that the capacitive element is formed.

If the sensing object F is not brought close to the sensing surface, anelectric field is generated between the scanning electrode 23J and thedetecting electrode 24J as shown in FIG. 30A when a common potentialVcom is applied to the scanning electrode 23J, which serves as the driveelectrode.

On the other hand, if the sensing object F having high electrostaticcapacitance, such as a finger, is brought close to the sensing surface,as shown in FIG. 30B, the fringe electric field (the dotted-line part inthe diagram) is blocked by the sensing object F.

Therefore, the electrostatic capacitance based on the scanning electrode23J and the detecting electrode 24J varies depending on whether or notthe sensing object F is present. Thus, based on the change in theelectrostatic capacitance, the position at which the sensing object F isbrought close to the sensing surface is detected.

However, in the case of the above-described capacitive touch sensor, itsdetection sensitivity is often not sufficiently high and thus it isoften difficult to detect the touch position with high accuracy.

For example, if the electrostatic capacitance based on the scanningelectrode and the detecting electrode is significantly lower than theparasitic capacitance of the detector, the detection is often notfavorable, which causes the need to increase the width of the detectingelectrode. However, in this case, the fringe electric field is blockedby this wide detecting electrode, and thus the lowering of the detectionsensitivity often occurs.

Furthermore, if the detecting electrode is formed as a transparentelectrode composed of ITO or the like, an attempt to ensure highertransparency of the detecting electrode raises the resistivity of thedetecting electrode and thus causes increase in the time constant. Thisoften results in a long detection time.

As above, the touch sensor often involves insufficient detectionsensitivity and a long detection time, and therefore it is oftendifficult for the touch sensor to perform the detection with highaccuracy.

There is a need for the present invention to provide a display deviceand an information input device that can easily realize detection withhigh accuracy.

SUMMARY OF THE INVENTION

According to an embodiment of the present invention, there is providedan information input device including a touch panel configured to beprovided with a touch sensor that detects a position at which a sensingobject is brought close to a sensing surface. In this information inputdevice, the touch sensor has a scanning electrode and a detectingelectrode that is opposed to the scanning electrode with theintermediary of a dielectric substance, and is a capacitive sensor whoseelectrostatic capacitance changes if the sensing object is brought closeto the detecting electrode. Furthermore, a slit is formed in a surfaceof the detecting electrode opposed to the scanning electrode.

According to another embodiment of the present invention, there isprovided a display device including a display panel configured to beprovided with a touch sensor that detects a position to which a sensingobject is brought close in a display surface for displaying an image. Inthis display device, the touch sensor has a scanning electrode and adetecting electrode that is opposed to the scanning electrode with theintermediary of a dielectric substance, and is a capacitive sensor whoseelectrostatic capacitance changes if the sensing object is brought closeto the detecting electrode. Furthermore, a slit is formed in a surfaceof the detecting electrode opposed to the scanning electrode.

In the embodiments of the present invention, in the detecting electrodeof the capacitive touch sensor, the slit is formed in the surfaceopposed to the scanning electrode. This allows generation of the fringeelectric field via the slit.

The embodiments of the present invention can provide a display deviceand an information input device that can easily realize detection withhigh accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the outline of the configuration of adisplay device in a first embodiment of the present invention;

FIG. 2 is a diagram showing the entire configuration of a liquid crystalpanel in the first embodiment of the present invention;

FIG. 3 is a diagram showing the detailed configuration of the liquidcrystal panel in the first embodiment of the present invention;

FIG. 4 is a diagram showing the detailed configuration of the liquidcrystal panel in the first embodiment of the present invention;

FIG. 5 is a diagram showing the detailed configuration of the liquidcrystal panel in the first embodiment of the present invention;

FIG. 6 is a diagram showing the detailed configuration of counterelectrodes in the first embodiment of the present invention;

FIG. 7 is a diagram showing the detailed configuration of detectingelectrodes in the first embodiment of the present invention;

FIG. 8 is a diagram showing the detailed configuration of a sensordriver in the first embodiment of the present invention;

FIG. 9 is a circuit diagram showing a detector in the first embodimentof the present invention;

FIGS. 10A and 10B are diagrams for explaining the operation of touchsensors in the first embodiment of the present invention;

FIGS. 11A and 11B are waveform diagrams respectively showing a detectionsignal and a drive signal in the first embodiment of the presentinvention;

FIGS. 12A and 12B are diagrams schematically showing the appearance whenthe touch sensor is driven in the first embodiment of the presentinvention;

FIGS. 13A and 13B are diagrams schematically showing the appearance whenthe touch sensor is driven in the first embodiment of the presentinvention;

FIG. 14 is a diagram showing a major part of a liquid crystal panel in asecond embodiment of the present invention;

FIG. 15 is a diagram showing a major part of the liquid crystal panel inthe second embodiment of the present invention;

FIG. 16 is a diagram showing the detailed configuration of counterelectrodes in the second embodiment of the present invention;

FIG. 17 is a diagram showing the outline of the configuration of adisplay device in a third embodiment of the present invention;

FIG. 18 is a diagram showing the configuration of a liquid crystal panelin the third embodiment of the present invention;

FIG. 19 is a diagram showing the configuration of a touch panel in thethird embodiment of the present invention;

FIG. 20 is a diagram showing the detailed configuration of counterelectrodes in the third embodiment of the present invention;

FIG. 21 is a diagram showing the detailed configuration of detectingelectrodes in the third embodiment of the present invention;

FIG. 22 is a diagram showing the detailed configuration of detectingelectrodes in a fourth embodiment of the present invention;

FIG. 23 is a diagram showing the detailed configuration of detectingelectrodes in a fifth embodiment of the present invention;

FIGS. 24A to 24D are diagrams showing the detailed configurations ofdetecting electrodes in modification examples of the embodiments of thepresent invention;

FIG. 25 is a diagram showing electronic apparatus to which the displaydevice of the embodiment of the present invention is applied;

FIG. 26 is a diagram showing electronic apparatus to which the displaydevice of the embodiment of the present invention is applied;

FIG. 27 is a diagram showing electronic apparatus to which the displaydevice of the embodiment of the present invention is applied;

FIG. 28 is a diagram showing electronic apparatus to which the displaydevice of the embodiment of the present invention is applied;

FIG. 29 is a diagram showing electronic apparatus to which the displaydevice of the embodiment of the present invention is applied; and

FIGS. 30A and 30B are diagrams showing the appearance when a capacitivetouch sensor is driven.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One example of embodiments of the present invention will be describedbelow.

The description will be made in the following order.

1. First Embodiment 2. Second Embodiment 3. Third Embodiment 4. FourthEmbodiment 5. Fifth Embodiment 6. Others 1. First Embodiment (A)Configuration of Display Device

FIG. 1 is a diagram showing the outline of the configuration of adisplay device 100 in a first embodiment of the present invention.

As shown in FIG. 1, the display device 100 of the present embodiment hasa liquid crystal panel 200, a backlight 300, and a data processor 400.These respective units will be sequentially described below.

(A-1) Liquid Crystal Panel

The liquid crystal panel 200 is based on e.g. the active-matrix systemand has a TFT array substrate 201, a counter substrate 202, and a liquidcrystal layer 203 as shown in FIG. 1. In the liquid crystal panel 200,the TFT array substrate 201 and the counter substrate 202 are opposed toeach other at an interval therebetween. The liquid crystal layer 203 isprovided between these substrates.

For the liquid crystal panel 200, as shown in FIG. 1, a first polarizer206 is disposed on the lower surface of the TFT array substrate 201 onthe opposite side to the upper surface thereof opposed to the countersubstrate 202. Furthermore, a second polarizer 207 is disposed on theupper surface of the counter substrate 202 on the opposite side to thelower surface thereof opposed to the TFT array substrate 201. Inaddition, a cover glass 208 is disposed on the upper surface of thesecond polarizer 207.

For the liquid crystal panel 200, as shown in FIG. 1, the backlight 300is disposed below the TFT array substrate 201. The lower surface of theTFT array substrate 201 is irradiated with illuminating light R emittedfrom the backlight 300.

The liquid crystal panel 200 of the present embodiment is a transmissivepanel. The illuminating light R passes through a display area PA, sothat image displaying is carried out.

As described in detail later, plural pixels (not shown) are disposed inthe display area PA. In this display area PA, the illuminating light Remitted from the backlight 300 provided on the back surface side of theliquid crystal panel 200 is received by the back surface via the firstpolarizer 206, and the illuminating light R received by the back surfaceis modulated. Over the TFT array substrate 201, plural TFTs are providedas pixel switching elements (not shown) corresponding to the pluralpixels. Through control of the pixel switching elements, theilluminating light R received by the back surface is modulated. Themodulated illuminating light R is output to the front surface side viathe second polarizer 207, so that an image is displayed in the displayarea PA. For example, a color image is displayed on the front surfaceside of the liquid crystal panel 200.

In addition, in the present embodiment, this liquid crystal panel 200includes touch sensors (not shown) of the “capacitive type.” The touchsensor is so configured as to output a signal of a different potentialdepending on the position at which a sensing object F such as a fingerof the user is brought into contact with the front surface of the liquidcrystal panel 200 on the opposite side to the back surface side, atwhich the backlight 300 is provided. That is, the liquid crystal panel200 functions not only as a display panel but also as a touch panel.This feature allows the display device 100, which is a liquid crystaldisplay device, to function as an information input device.

(A-2) Backlight

The backlight 300 is opposed to the back surface of the liquid crystalpanel 200 and emits the illuminating light R to the display area PA ofthe liquid crystal panel 200 as shown in FIG. 1.

Specifically, the backlight 300 is located below the TFT array substrate201, and emits the illuminating light R to the surface of the TFT arraysubstrate 201 on the opposite side to the surface thereof opposed to thecounter substrate 202. That is, the backlight 300 emits the illuminatinglight R in such a way that the illuminating light R is directed from theside of the TFT array substrate 201 toward the side of the countersubstrate 202. In this configuration, the backlight 300 emits theilluminating light R along the normal direction z of the surface of theliquid crystal panel 200.

(A-3) Data Processor

The data processor 400 has a controller 401 and a position detector 402as shown in FIG. 1. The data processor 400 includes a computer and is soconfigured that the computer operates as the controller 401 and theposition detector 402 based on a program.

In the data processor 400, the controller 401 is so configured as tocontrol the operation of the liquid crystal panel 200 and the backlight300. The controller 401 supplies a control signal to the liquid crystalpanel 200 to thereby control the operation of the plural pixel switchingelements (not shown) provided in the liquid crystal panel 200. Forexample, the controller 401 makes the liquid crystal panel 200 carry outline-sequential driving. Furthermore, the controller 401 supplies acontrol signal to the backlight 300 to thereby control the operation ofthe backlight 300 and make the backlight 300 emit the illuminating lightR. In this manner, the controller 401 controls the operation of theliquid crystal panel 200 and the backlight 300 to thereby display animage in the display area PA of the liquid crystal panel 200.

In addition, the controller 401 supplies a control signal to the liquidcrystal panel 200 to thereby control the operation of the touch sensorsprovided in the liquid crystal panel 200 and collect detection data fromthe touch sensors.

The position detector 402 in the data processor 400 is so configured asto detect the coordinate position at which the sensing object F such asa finger of a human body is brought close to the display area PA on thefront surface (display surface) side of the liquid crystal panel 200. Inthe present embodiment, the position detector 402 carries out thedetection of the coordinate position based on the detection dataobtained by the touch sensors provided in the liquid crystal panel 200.

(B) Entire Configuration of Liquid Crystal Panel

The entire configuration of the liquid crystal panel 200 will bedescribed below.

FIG. 2 is a diagram showing the entire configuration of the liquidcrystal panel 200 in the first embodiment of the present invention. FIG.2 is a plan view of the liquid crystal panel 200.

As shown in FIG. 2, the liquid crystal panel 200 has the display area PAand a peripheral area CA.

In the liquid crystal panel 200, plural pixels P are disposed in thedisplay area PA along the surface as shown in FIG. 2. Specifically, inthe display area PA, the plural pixels P are arranged in a matrix alongeach of the horizontal direction x and the vertical direction y, andimages are displayed therein.

As described in detail later, the pixels P each include theabove-described pixel switching element (not shown). Furthermore, theplural touch sensors (not shown) are so provided as to correspond to theplural pixels P.

In the liquid crystal panel 200, the peripheral area CA is so located asto surround the display area PA as shown in FIG. 2. In this peripheralarea CA, a vertical drive circuit 11 and a horizontal drive circuit 12are formed as shown in FIG. 2. These respective circuits are formed byusing e.g. semiconductor elements formed similarly to theabove-described pixel switching elements (not shown).

The vertical drive circuit 11 and the horizontal drive circuit 12 drivethe pixel switching elements provided corresponding to the pixels P tothereby carry out image displaying in the display area PA.

In addition, the vertical drive circuit 11 is so configured as to drivethe touch sensors (not shown) provided in the display area PA, and adetector (not shown) is provided in the peripheral area CA so as todetect the detection data obtained by driving of the touch sensors.Based on the detection data acquired from the touch sensors, theposition detector 402 detects the position at which a sensing objectsuch as a finger of the user is brought into contact with the displayarea PA of the liquid crystal panel 200.

(C) Detailed Configuration of Liquid Crystal Panel

The detailed configuration of the liquid crystal panel 200 will bedescribed below.

FIG. 3, FIG. 4, and FIG. 5 are diagrams showing the detailedconfiguration of the liquid crystal panel 200 in the first embodiment ofthe present invention.

FIG. 3 is a sectional view schematically showing the outline of thepixels P. FIG. 4 is a circuit diagram showing the outline of the pixelP. FIG. 5 is a circuit diagram showing the outline of a touch sensor TS.

The liquid crystal panel 200 has the TFT array substrate 201 and thecounter substrate 202 as shown in FIG. 3. Spacers (not shown) areinterposed between the TFT array substrate 201 and the counter substrate202 and these substrates are bonded to each other by a sealing material(not shown). The liquid crystal layer 203 is enclosed between the TFTarray substrate 201 and the counter substrate 202.

Furthermore, in the present embodiment, the touch sensors TS areprovided in the liquid crystal panel 200 as shown in FIG. 3. Therefore,the liquid crystal panel 200 is so configured as to function not only asa display panel but also as a touch panel.

The touch sensor TS includes a capacitive element C1 formed by a counterelectrode 23 and a detecting electrode 24 as shown in FIG. 5, and is soconfigured that the electrostatic capacitance of the capacitive elementC1 changes when a sensing object (not shown) is brought close to thedetecting electrode 24.

The respective components of the liquid crystal panel 200 will bedescribed below.

(C-1) TFT Array Substrate

Details of the TFT array substrate 201 included in the liquid crystalpanel 200 will be described below.

The TFT array substrate 201 is a substrate composed of anoptically-transparent insulator and is formed of e.g. glass. As shown inFIG. 3, pixel switching elements 31 and pixel electrodes 62 p are formedover the TFT array substrate 201.

The respective components provided over the TFT array substrate 201 willbe described below.

As shown in FIG. 3, the pixel switching elements 31 are provided on thesurface of the TFT array substrate 201 opposed to the counter substrate202. The pixel switching element 31 is e.g. a bottom-gate TFT formed byusing poly-silicon.

In the TFT serving as the pixel switching element 31, the gate electrodeis electrically connected to a gate line GL as shown in FIG. 4.

As shown in FIG. 4, the gate line GL extends along the x direction.Although not shown in FIG. 3, the gate line GL is formed monolithicallywith the gate electrode of the pixel switching element 31 on the surfaceof the TFT array substrate 201 shown in FIG. 3. For example, the gateline GL is formed by using a metal material such as molybdenum and formsa light-blocking area that does not transmit light but blocks light inthe liquid crystal panel 200.

Furthermore, as shown in FIG. 4, the gate line GL is electricallyconnected to the vertical drive circuit 11. To the gate electrode of thepixel switching element 31, a scan signal Vgate is supplied from thevertical drive circuit 11 via the gate line GL.

One source/drain region of the TFT serving as the pixel switchingelement 31 is electrically connected to a signal line SL as shown inFIG. 4.

As shown in FIG. 4, the signal line SL is so formed as to extend alongthe y direction and is electrically connected to the horizontal drivecircuit 12. The signal line SL outputs, to the pixel switching element31, a video data signal input from the horizontal drive circuit 12.

The signal line SL is provided in an interlayer insulating film 60 thatis so formed on the TFT array substrate 201 as to cover the pixelswitching elements 31 although not shown in FIG. 3. The signal line SLis formed by using e.g. an electrically-conductive material that blockslight. Specifically, the signal line SL is formed by using a metalmaterial and forms a light-blocking area that does not transmit lightbut blocks light in the liquid crystal panel 200.

On the other hand, the other source/drain region of the pixel switchingelement 31 is electrically connected to the pixel electrode 62 p asshown in FIG. 4.

As shown in FIG. 3, the pixel electrodes 62 p are provided over thesurface of the TFT array substrate 201 opposed to the counter substrate202 with the intermediary of the interlayer insulating film 60. Thepixel electrode 62 p is a so-called transparent electrode and is formedby using e.g. ITO.

As shown in FIG. 4, the pixel electrode 62 p is electrically connectedto the pixel switching element 31, and receives the video data signalinput from the horizontal drive circuit 12 to apply voltage to theliquid crystal layer 203 when the pixel switching element 31 is set tothe on-state. Thereby, the alignment direction of the liquid crystalmolecules included in the liquid crystal layer 203 changes and the lightpassing through the liquid crystal layer 203 is modulated, so that imagedisplaying is carried out.

(C-2) Counter Substrate 202

The counter substrate 202 included in the liquid crystal panel 200 willbe described below.

The counter substrate 202 is a substrate composed of anoptically-transparent insulator similarly to the TFT array substrate201, and is formed of e.g. glass. As shown in FIG. 3, this countersubstrate 202 is opposed to the TFT array substrate 201 at an intervaltherebetween. Around the counter substrate 202, a color filter layer 21,the counter electrodes 23, and the detecting electrodes 24 are formed.

The respective components provided around the counter substrate 202 willbe described below.

As shown in FIG. 3, the color filter layer 21 is formed on the surfaceof the counter substrate 202 opposed to the TFT array substrate 201. Thecolor filter layer 21 includes a red filter 21R, a green filter 21G, anda blue filter 21B, and the respective filters are so formed as to bearranged along the x direction. That is, in the color filter layer 21,the filters of three primary colors, i.e. red, green, and blue, aretreated as one set, and the filters of the respective colors areprovided for each pixel P. The color filter layer 21 is formed by usinge.g. a polyimide resin in which colorants such as pigments or dyes arecontained corresponding to the respective colors. White light emittedfrom the backlight 300 is colored by the color filter layer 21 and thenoutput therefrom.

As shown in FIG. 3, a planarizing film 22 covers the surface of thecolor filter layer 21 opposed to the TFT array substrate 201. Thisplanarizing film 22 is formed by using an optically-transparentinsulating material and planarizes the side of the surface of thecounter substrate 202 opposed to the TFT array substrate 201.

As shown in FIG. 3, the counter electrodes 23 are formed over thesurface of the counter substrate 202 opposed to the TFT array substrate201. The counter electrodes 23 are so formed as to cover the planarizingfilm 22. The counter electrode 23 is a transparent electrode thattransmits visible light and is formed by using e.g. ITO.

As shown in FIG. 3, the counter electrodes 23 are so formed that theliquid crystal layer 203 is sandwiched between the counter electrodes 23and the pixel electrodes 62 p, and are so configured as to function as acommon electrode that applies voltage to the liquid crystal layer 203sandwiched between the counter electrodes 23 and the pixel electrodes 62p.

In addition, in the present embodiment, the counter electrode 23 is soprovided that a dielectric substance (in FIG. 3, the counter substrate202 and so on) is sandwiched between the counter electrode 23 and thedetecting electrode 24 and thereby the capacitive element C1 is formedas shown in FIG. 3 and FIG. 5. That is, the counter electrode 23 is soprovided as to form the capacitive touch sensor TS together with thedetecting electrode 24. As shown in FIG. 5, the counter electrode 23 iselectrically connected to a sensor driver S, and a drive signal Sgoutput from the sensor driver S is input to the counter electrode 23.

FIG. 6 is a diagram showing the detailed configuration of the counterelectrodes 23 in the first embodiment of the present invention. FIG. 6is a top view of the counter electrodes 23.

As shown in FIG. 6, the counter electrodes 23 are in a stripe manner andextend along the horizontal direction x over the surface of the countersubstrate 202. Furthermore, the counter electrodes 23 are so disposedthat plural electrodes are arranged at intervals in the verticaldirection y. Specifically, n electrodes, i.e. first to n-th counterelectrodes 23_1 to 23_n, are provided as the counter electrodes 23 inthe direction from the upper side toward the lower side. In thisconfiguration, the plural counter electrodes 23 are disposed with anequivalent interval in such a manner as to be opposed to each of theplural pixel electrodes 62 p arranged along the vertical direction y.

Each of the first to n-th counter electrodes 23_1 to 23_n iselectrically connected to the sensor driver S as shown in FIG. 6. Eachof the first to n-th counter electrodes 23_1 to 23_n is sequentiallyselected to be supplied with the drive signal Sg output from the sensordriver S. That is, each of the first to n-th counter electrodes 23_1 to23_n is supplied with the drive signal Sg based on line-sequential scandriving.

The detecting electrodes 24 are formed on the surface of the countersubstrate 202 on the opposite side to the surface thereof opposed to theTFT array substrate 201 as shown in FIG. 3. The detecting electrode 24is a transparent electrode that transmits visible light and is formed byusing e.g. ITO.

As shown in FIG. 3 and FIG. 5, the detecting electrode 24 and thecounter electrode 23 sandwich a dielectric substance (in FIG. 3, thecounter substrate 202 and so on), and form the capacitive touch sensorTS. Furthermore, as shown in FIG. 5, the detecting electrode 24 iselectrically connected to a detector DET and grounded via a resistor R.The detecting electrode 24 is so configured as to output a detectionsignal Vdet to the detector DET.

As described in detail later, if a sensing object as a conductive bodyhaving high capacity, such as a finger, is brought close to thedetecting electrode 24, the fringe electric field by the counterelectrode 23 to which the drive signal Sg is input is blocked by thesensing object. Thus, the capacitance changes depending on whether ornot the sensing object is present, and the potential of the detectingelectrode 24 changes. Therefore, the contact position can be detected bydetecting this potential change via the detector DET.

FIG. 7 is a diagram showing the detailed configuration of the detectingelectrodes 24 in the first embodiment of the present invention. FIG. 7is a top view of the detecting electrodes 24.

As shown in FIG. 7, the detecting electrodes 24 are in a stripe mannerand extend along the vertical direction y on the surface of the countersubstrate 202. Furthermore, the detecting electrodes 24 are so disposedthat plural electrodes are arranged at intervals in the horizontaldirection x. Specifically, k electrodes, i.e. first to k-th detectingelectrodes 24_1 to 24_k, are provided as the detecting electrodes 24 inthe direction from the left side toward the right side.

Each of the first to k-th detecting electrodes 24_1 to 24_k iselectrically connected to the detector DET as shown in FIG. 7. Asdescribed in detail later, each of the first to k-th detectingelectrodes 24_1 to 24_k outputs the detection signal Vdet to thedetector DET.

In the present embodiment, as shown in FIG. 7, slits KK are formed inthe surface of each of the detecting electrodes 24 opposed to thecounter electrodes 23. The slits KK extend along the vertical directiony inside each detecting electrode 24 and are so provided that pluralslits are arranged at intervals in the horizontal direction x. Forexample, it is preferable that the width of the slit KK be 100 to 1100μm.

(C-3) Liquid Crystal Layer 203

The liquid crystal layer 203 included in the liquid crystal panel 200will be described below.

The liquid crystal layer 203 is sandwiched between the TFT arraysubstrate 201 and the counter substrate 202 opposed to each other asshown in FIG. 3.

In this configuration, the liquid crystal molecules (not shown) in theliquid crystal layer 203 are aligned by a liquid crystal alignment film(not shown) formed over the TFT array substrate 201 and a liquid crystalalignment film (not shown) formed over the counter substrate 202. Forexample, the liquid crystal layer 203 is so formed that the liquidcrystal molecules are vertically aligned. The liquid crystal layer 203is so configured that the alignment direction of the liquid crystalmolecules changes due to voltage application by the pixel electrode 62 pand the counter electrode 23. The liquid crystal layer 203 may be soformed as to conform to the TN (Twisted Nematic) mode or the ECB(Electrically Controlled Birefringence) mode, besides the VA (VerticalAlignment) mode.

(C-4) Sensor Driver S

The detailed configuration of the sensor driver S electrically connectedto the counter electrodes 23 will be described below.

FIG. 8 is a diagram showing the detailed configuration of the sensordriver S in the first embodiment of the present invention.

As shown in FIG. 8, the sensor driver S has a controller 91, a firstswitch SW1, a second switch SW2, a latch circuit 92, a buffer circuit93, and a third switch SW3, and is so configured as to function as an ACcurrent source. The sensor driver S applies, to the counter electrode23, the drive signal Sg that is e.g. an AC rectangular wave with afrequency of several kilohertz to several tens of kilohertz and is acommon potential Vcom.

The respective components included in the sensor driver S will besequentially described below.

In the sensor driver S, the controller 91 is formed as a circuit thatcontrols the switching operation of each of the first switch SW1, thesecond switch SW2, and the third switch SW3 as shown in FIG. 8.

In the sensor driver S, one terminal of the first switch SW1 iselectrically connected to the latch circuit 92 as shown in FIG. 8. Thefirst switch SW1 is so configured that a positive voltage V(+) isapplied to the latch circuit 92 when the first switch SW1 is set to theon-state by the switching control by the controller 91.

In the sensor driver S, one terminal of the second switch SW2 iselectrically connected to the latch circuit 92 as shown in FIG. 8. Thesecond switch SW2 is so configured that a negative voltage V(−) isapplied to the latch circuit 92 when the second switch SW2 is set to theon-state by the control by the controller 91.

In the sensor driver S, the input terminal of the latch circuit 92 iselectrically connected to each of the first switch SW1 and the secondswitch SW2. The output terminal of the latch circuit 92 is electricallyconnected to the third switch SW3 via the buffer circuit 93.

In the sensor driver S, the buffer circuit 93 is a waveform shaping unitand is provided as a circuit that carries out potential compensation ofthe input potential for the positive voltage V(+) and the negativevoltage V(−) and outputs the resulting voltage.

In the sensor driver S, the switching operation of the thirdsemiconductor SW3 is controlled by the controller 91. The third switchSW3 is electrically connected to the counter electrode 23 when being setto the on-state. On the other hand, the third switch SW3 becomes theinactive GND-connected state when being set to the off-state.

The sensor driver S having this configuration is so provided as tocorrespond to each of the plural counter electrodes 23.

The above-described sensor driver S is included in the vertical drivecircuit 11 (see FIG. 2) in the peripheral area CA located around thedisplay area PA on the TFT array substrate 201 for example.Alternatively, it may be provided in the peripheral area CA on thecounter substrate 202.

(C-5) Detector DET

The detailed configuration of the detector DET electrically connected tothe detecting electrode 24 will be described below.

FIG. 9 is a circuit diagram showing the detector DET in the firstembodiment of the present invention.

As shown in FIG. 9, the detector DET includes an OP-Amp circuit 81, arectifier circuit 82, and an output circuit 83.

The respective components included in the detector DET will besequentially described below.

In the detector DET, the OP-Amp circuit 81 includes an OP-Amp 84,resistors R, R1, and R2, and a capacitor C3 as shown in FIG. 9, and isso configured as to function as a filter circuit in addition to a signalamplifying circuit. Specifically, the OP-Amp circuit 81 amplifies thedetection signal Vdet output from the detecting electrode 24, and thenremoves a predetermined frequency component from the detection signalVdet to output the resulting signal to the rectifier circuit 82.

More specifically, as shown in FIG. 9, in the OP-Amp circuit 81, thedetecting electrode 24 is electrically connected to the positive inputterminal (+) of the OP-Amp 84, and the detection signal Vdet output fromthe detecting electrode 24 is input to the positive input terminal (+).In this configuration, the detecting electrode 24 is connected to theground potential via the resistor R in order to electrically fix the DClevel of the potential. The resistor R2 and the capacitor C3 areconnected in parallel between the negative input terminal (−) of theOP-Amp 84 and the output terminal thereof, and the resistor R1 isconnected between the negative input terminal (−) of the OP-Amp 84 andthe ground potential.

In the detector DET, the rectifier circuit 82 has a diode D1, a chargingcapacitor C4, and a discharging resistor R0 as shown in FIG. 9. Thisrectifier circuit 82 is so configured that the signal output from theOP-Amp circuit 81 is half-wave rectified by the diode D1 and then thesignal is smoothed by the smoothing circuit composed of the chargingcapacitor C4 and the discharging resistor R0 to be output to the outputcircuit 83.

Specifically, in the rectifier circuit 82, the anode of the diode D1 iselectrically connected to the output terminal of the OP-Amp circuit 81as shown in FIG. 9. Each of the charging capacitor C4 and thedischarging resistor R0 is electrically connected between the cathode ofthe diode D1 and the ground potential.

In the detector DET, the output circuit 83 includes a comparator 85 asshown in FIG. 9, and is so configured as to function as an AD converterthat converts the analog signal output from the rectifier circuit 82 toa digital signal.

Specifically, as shown in FIG. 9, the negative input terminal (−) of thecomparator 85 is electrically connected to the rectifier circuit 82.Furthermore, a threshold voltage Vth is input to the positive inputterminal (+) of the comparator 85. The comparator 85 executes processingof comparison between the analog signal output from the rectifiercircuit 82 and the threshold voltage Vth, and outputs the digital signalbased on the result of the processing.

The above-described detector DET is provided in the peripheral area CAlocated around the display area PA on the counter substrate 202 forexample. Alternatively, it may be provided in the peripheral area CA onthe TFT array substrate 201.

(D) Operation

The operation of the above-described display device 100 will bedescribed below.

The operation at the time of image displaying in the above-describeddisplay device 100 will be described.

In the image displaying, the controller 401 controls the operation ofthe liquid crystal panel 200 (see FIG. 1). Furthermore, the controller401 supplies a control signal to the backlight 300 to thereby controlthe operation of the backlight 300 and make the backlight 300 emit theilluminating light R (see FIG. 1).

In this case, the controller 401 supplies a control signal to the liquidcrystal panel 200 to thereby drive the plural pixels P provided in theliquid crystal panel 200 (see FIG. 2). In this configuration, thevertical drive circuit 11 and the horizontal drive circuit 12 drive theplural pixels P disposed in the display area PA.

Specifically, the vertical drive circuit 11 supplies a drive signal tothe gates of the pixel switching elements 31 via the gate line GL andturns the pixel switching elements 31 to the on-state (see FIG. 4).

In addition, the vertical drive circuit 11 supplies the drive signal Sgto each of the plural counter electrodes 23. In this configuration, thevertical drive circuit 11 line-sequentially selects the plural counterelectrodes 23 arranged in the vertical direction y and supplies thedrive signal Sg to the selected counter electrodes 23. Specifically,each of the first to n-th counter electrodes 23_1 to 23_n is suppliedwith the drive signal Sg based on line-sequential scan driving and setto the common potential Vcom. That is, the vertical drive circuit 11functions as the above-described sensor driver S (see FIG. 8 and so on).

Furthermore, at this time, the horizontal drive circuit 12 suppliesvideo signals from the signal lines SL to the pixel electrodes 62 p viathe pixel switching elements 31.

Thus, an electric field is applied to the liquid crystal layer 203between the pixel electrodes 62 p and the counter electrodes 23 and thealignment of the liquid crystal molecules in the liquid crystal layer203 changes, so that the light passing through the liquid crystal layer203 is modulated. Consequently, image displaying is carried out in thedisplay area PA.

The above-described image displaying operation is carried out based onthe Vcom inversion driving system.

A description will be made below about operation at the time ofdetection of the position at which the sensing object F such as a fingerof the user is brought into contact with the display area PA of theliquid crystal panel 200 in the above-described display device 100.

FIGS. 10A and 10B are diagrams for explaining the operation of the touchsensors TS in the first embodiment of the present invention. FIGS. 10Aand 10B are top views showing the counter electrodes 23 and thedetecting electrodes 24. In FIGS. 10A and 10B, of the plural counterelectrodes 23, the counter electrodes 23 that are supplied with thedrive signal Sg by the vertical drive circuit 11 and set to the commonpotential Vcom in the above-described image displaying operation arerepresented as hatched areas.

In the above-described image displaying operation, some of the pluralcounter electrodes 23 are selected and supplied with the drive signal Sgas shown by the hatched areas in FIGS. 10A and 10B.

In the present embodiment, as shown in FIGS. 10A and 10B, m counterelectrodes (23_1 to m, 23_2 to m+1, . . . ) of n counter electrodes 23_1to n (m<n) are selected and supplied with the drive signal Sg. That is,m counter electrodes 23 are simultaneously set to the common potentialVcom.

m counter electrodes 23 as the selected electrodes are shifted in thevertical direction y and the above-described supply of the drive signalSg is carried out.

For example, as shown by the hatched areas in FIG. 10A, the counterelectrodes 23 from the first counter electrode 23_1 to the m-th counterelectrode 23_m are selected. Furthermore, the drive signal Sg issupplied to these selected counter electrodes 23 from the first counterelectrode 23_1 to the m-th counter electrode 23_m.

Subsequently, as shown by the hatched areas in FIG. 10B, the counterelectrodes 23 from the second counter electrode 23_2 to the (m+1)-thcounter electrode 23_m+1 are selected. Furthermore, the drive signal Sgis supplied to these selected counter electrodes 23 from the secondcounter electrode 23_2 to the (m+1)-th counter electrode 23_m+1.

In this manner, in the image displaying operation, consecutive m counterelectrodes 23 of n counter electrodes 23 (m<n) are selected and the Vcominversion driving (AC driving) is carried out. Furthermore, the shiftoperation of changing these selected electrodes in the verticaldirection y is so carried out that at least one counter electrode 23 iscommon between before and after each shift operation. The Vcom inversiondriving is carried out for m counter electrodes 23 selected through theshift operation.

When the counter electrodes 23 are supplied with the drive signal Sg andset to the common potential Vcom in the above-described manner, a chargeis accumulated in the capacitive elements at the intersections of thesecounter electrodes 23 and the detecting electrodes 24 as shown in FIGS.10A and 10B. Furthermore, when the shift operation is carried out in theabove-described manner, charging and discharging are carried out at thecapacitive elements at the intersections of the counter electrodes 23and the detecting electrodes 24. In this configuration, the rows of thecapacitive elements as the targets of the charging and discharging areline-sequentially moved in linkage with the scanning by the drive signalSg. Thus, the detection signal Vdet with the signal intensity dependenton the capacitance of the capacitive element is output from each of thedetecting electrodes 24 to a respective one of the detectors DET.

Based on the detection signals Vdet output from the detectors DET, theposition detector 402 in the data processor 400 (see FIG. 1) performsposition detection.

FIGS. 11A and 11B are waveform diagrams showing the drive signal Sg andthe detection signal Vdet in the first embodiment of the presentinvention.

As shown in FIGS. 11A and 11B, when the drive signal Sg as a rectangularwave is output to the counter electrode 23, the detection signal Vdet isoutput from the detecting electrode 24.

If a sensing object is not brought close to the detecting electrode 24,a detection signal Vdet0 is output with signal intensity higher than thethreshold Vth as shown in FIG. 11A. In this case, each of the detectionsignals Vdet0 output from the plural detecting electrodes 24 has almostconstant signal intensity.

On the other hand, if a sensing object having high electrostaticcapacitance, such as a finger, is brought close to the detectingelectrode 24, the fringe electric field (see FIG. 30B) is blocked by thesensing object. Thus, the electrostatic capacitance based on the counterelectrode 23 and the detecting electrode 24 varies depending on whetheror not the sensing object is present. Therefore, a detection signalVdet1 with signal intensity lower than the above-described threshold Vthis output as shown in FIG. 11A. Consequently, the signal intensity ofeach of the detection signals Vdet output from the plural detectingelectrodes 24 varies depending on whether or not the sensing object ispresent, and thus the position at which the sensing object F is broughtclose to the sensing surface is detected. In this configuration, thetouch position coordinates can be obtained based on the timing of theapplication of the drive signal Sg and the timing of the detection bythe detectors DET.

By making the touch sensor TS operate in the above-described manner, thelowering of the sensor voltage and the lowering of the image quality dueto the switching of the electrode driving can be prevented.

FIGS. 12A and 12B are diagrams schematically showing the appearance whenthe touch sensor TS is driven in the first embodiment of the presentinvention. FIG. 12A shows the case in which the sensing object F is notbrought close to the sensing surface of the touch sensor TS. On theother hand, FIG. 12B shows the case in which the sensing object F isbrought close to the sensing surface.

As shown in FIGS. 12A and 12B, the slit KK is formed in the surface ofthe detecting electrode 24 opposed to the counter electrode 23.

As shown in FIG. 12A, if the sensing object F is not brought close tothe sensing surface (display surface), an electric field is generatedbetween the counter electrode 23 and the detecting electrode 24 when thecommon potential Vcom is applied to the counter electrode 23. In thepresent embodiment, the fringe electric field via the slit KK providedin the detecting electrode 24 is also generated in addition to theelectric field between the flat plates of the counter electrode 23 andthe detecting electrode 24.

If the sensing object F such as a finger is brought close to the sensingsurface (display surface), as shown in FIG. 12B, the fringe electricfield (the dotted-line part in the diagram) is blocked by this sensingobject F. In the present embodiment, the fringe electric field via theslit KK provided in the detecting electrode 24 is also blocked and thusnot generated.

Consequently, the change in the electrostatic capacitance dependent onwhether or not the sensing object F is present is larger when the slitKK is provided in the detecting electrode 24 than when the slit KK isnot provided.

Thus, in the present embodiment, the detection sensitivity of the touchsensor TS can be enhanced by providing the slit KK in the detectingelectrode 24. Furthermore, by keeping the total value of the width ofthe part of the detecting electrode 24 other than the part in which theslit KK is provided, the resistance can be kept even when the width ofthe whole of the detecting electrode 24 becomes larger. This can preventincrease in the time constant in the detecting electrode 24. Therefore,extension of the detection time can be prevented.

It is preferable for the slit KK to have a larger slit width.

FIGS. 13A and 13B are diagrams schematically showing the appearance whenthe touch sensor TS is driven in the first embodiment of the presentinvention. FIG. 13A shows the case in which the slit width is small. Onthe other hand, FIG. 13B shows the case in which the slit width islarge.

As shown in FIG. 13A, if the slit width of the slit KK is small, onlythe fringe electric field attributed to the near part of the counterelectrode 23 is generated.

On the other hand, as shown in FIG. 13B, if the slit width of the slitKK is large, not only the fringe electric field attributed to the nearpart of the counter electrode 23 but also the fringe electric fieldattributed to the farther part is generated.

Therefore, when the slit width of the slit KK is large, the ratio of thefringe electric field blocked by the sensing object F when the sensingobject F is brought into contact with the detecting electrode 24 ishigher than when the slit width is small, and thus higher detectionsensitivity can be achieved.

For example, when the width of the slit KK provided on the countersubstrate was set to 200 μm, 300 μm, 500 μm, and 1100 μm undersimulation conditions shown below, the detection sensitivity was about8%, about 10%, about 11%, and about 14%, respectively, and thus largerslit width was more preferable. This “sensitivity” refers to the ratioof the amount of change in the output voltage due to finger placementwith respect to the amount of change in the output voltage obtained whenthe finger is absent, and the ratio is represented as the percentage.

-   -   the thickness of the counter substrate (color filter substrate):        300 μm    -   the relative dielectric constant of the counter substrate (color        filter substrate): 4    -   the thickness of the polarizer (on the counter substrate): 125        μm    -   the relative dielectric constant of the polarizer: 5

The sensitivity is higher when the width of the whole of the detectingelectrode (the width of the whole including the slit), whose maximumvalue is equivalent to the finger size, is larger. The reason for thisis that the contact area with the finger is increased, and the optimumwidth of the detecting electrode is e.g. about 4 to 8 mm, which isequivalent to the finger size.

(E) Summary

As above, in the display device 100 of the present embodiment, thecapacitive touch sensors TS for detecting the position to which thesensing object F is brought close are provided in the display surfacefor image displaying in the liquid crystal panel 200 (see FIG. 3). Thistouch sensor TS has the counter electrode 23 and the detecting electrode24, and the detecting electrode 24 is opposed to the counter electrode23 with the intermediary of a dielectric substance. The electrostaticcapacitance changes when the sensing object F is brought close to thedetecting electrode 24. Furthermore, the slit KK is formed in thesurface of the detecting electrode 24 opposed to the counter electrode23.

Thus, as described above, the touch sensor TS of the present embodimentcan achieve larger change as the change in the electrostatic capacitancedependent on whether or not the sensing object F is present, comparedwith the case in which the slit KK is not provided in the detectingelectrode 24.

Therefore, the present embodiment can enhance the detection sensitivityof the touch sensor and can carry out detection of the touch position ofthe sensing object F with high accuracy.

Furthermore, in the present embodiment, the plural counter electrodes 23function as scanning electrodes opposed to the plural detectingelectrodes 24 with the intermediary of the dielectric substance in thetouch sensors TS. In addition, the plural counter electrodes 23 functionas common electrodes opposed to the plural pixel electrodes 62 p withthe intermediary of the liquid crystal layer 203 in the pixels P forimage displaying. Because of this feature, the detection signal of thetouch sensor TS can be obtained by using the common drive signal Vcomfor the image displaying also as the drive signal for the touch sensor.That is, the counter electrode 23 is so configured as to be used as boththe common electrode for applying voltage to the liquid crystal layer203 for the image displaying and the scanning electrode included in thetouch sensor TS. Moreover, because a touch panel is not separatelyprovided as an external unit, small thickness can be obtained as thethickness of the entire device.

Thus, the present embodiment allows smaller thickness of the device andcan realize enhancement in the manufacturing efficiency and costreduction.

2. Second Embodiment

A second embodiment of the present invention will be described below.

(A) Detailed Configuration of Liquid Crystal Panel

The detailed configuration of a liquid crystal panel 200 b in thepresent embodiment will be described.

FIG. 14 and FIG. 15 are diagrams showing major parts of the liquidcrystal panel 200 b in the second embodiment of the present invention.

FIG. 14 is a sectional view schematically showing the outline of pixelsP provided in a display area PA in the liquid crystal panel 200 baccording to the second embodiment of the present invention.

FIG. 15 is a top view schematically showing the outline of the pixel Pprovided in the display area PA in the liquid crystal panel 200 baccording to the second embodiment of the present invention.

As shown in FIG. 14 and FIG. 15, in the liquid crystal panel 200 b ofthe present embodiment, pixel electrodes 62 pb and counter electrodes 23b are so formed as to conform to the fringe field switching (FFS)system. Except for this point and points relating thereto, the secondembodiment is the same as the first embodiment. Therefore, descriptionof the overlapping part is omitted.

The pixel electrodes 62 pb are formed over the surface of a TFT arraysubstrate 201 opposed to a counter substrate 202 as shown in FIG. 14.

Specifically, the pixel electrodes 62 pb are provided on an interlayerinsulating film 61 that is formed by using an insulating material insuch a manner as to cover the counter electrodes 23 b over the TFT arraysubstrate 201 as shown in FIG. 14. For example, they are provided on theinterlayer insulating film 61 formed as a silicon nitride film.

In the present embodiment, because the liquid crystal panel 200 b isbased on the FFS system, the pixel electrode 62 pb is sopattern-processed as to have a comb tooth shape in the xy plane as shownin FIG. 15.

Specifically, the pixel electrode 62 pb has a backbone part 62 bk andbranch parts 62 be as shown in FIG. 15.

In the pixel electrode 62 pb, the backbone part 62 bk extends along thex direction as shown in FIG. 15.

Furthermore, in the pixel electrode 62 pb, the branch parts 62 be areconnected to the backbone part 62 bk and extend along the y direction asshown in FIG. 15. The branch parts 62 be are so disposed that pluralparts are arranged at intervals in the x direction as shown in FIG. 15.Furthermore, both ends of each of the plural parts are connected to thebackbone part 62 bk, and the plural parts are so arranged as to extendin parallel to each other.

The counter electrodes 23 b are formed over the surface of the TFT arraysubstrate 201 opposed to the counter substrate 202 as shown in FIG. 14.Specifically, the counter electrodes 23 b are provided under theinterlayer insulating film 61 formed over the TFT array substrate 201.

FIG. 16 is a diagram showing the detailed configuration of the counterelectrodes 23 b in the second embodiment of the present invention. FIG.16 is a top view of the counter electrodes 23 b.

As shown in FIG. 16, the counter electrodes 23 b are in a stripe mannerand extend along the horizontal direction x similarly to the firstembodiment. Furthermore, the counter electrodes 23 b are so disposedthat plural electrodes are arranged at intervals in the verticaldirection y. Specifically, n electrodes, i.e. first to n-th counterelectrodes 23 b_1 to 23 b_n, are provided as the counter electrodes 23 bin the direction from the upper side toward the lower side. In thisconfiguration, the plural counter electrodes 23 b are disposed with anequivalent interval in such a manner as to be opposed to each of theplural pixel electrodes 62 pb arranged along the vertical direction y.

Each of the first to n-th counter electrodes 23 b_1 to 23 b_n iselectrically connected to a sensor driver S as shown in FIG. 16,similarly to the first embodiment. Each of the first to n-th counterelectrodes 23 b_1 to 23 b_n is sequentially selected to be supplied witha drive signal Sg output from the sensor driver S. That is, each of thefirst to n-th counter electrodes 23 b_1 to 23 b_n is supplied with thedrive signal Sg based on line-sequential scan driving.

Although not shown in the diagram, alignment treatment of the liquidcrystal layer 203 is so performed that the longitudinal direction of theliquid crystal molecules is set parallel to the direction of the xyplane, across which the TFT array substrate 201 and the countersubstrate 202 are opposed to each other. That is, the liquid crystallayer 203 is so formed that the liquid crystal molecules arehorizontally aligned.

In image displaying in the above-described liquid crystal panel 200 b, alateral electric field is applied to the liquid crystal layer 203 by thepixel electrodes 62 pb and the counter electrodes 23 b and the alignmentof the liquid crystal molecules in the liquid crystal layer 203 changes,so that the light passing through the liquid crystal layer 203 ismodulated.

The operation of detecting the position at which a sensing object F suchas a finger of the user is brought into contact with the display area PAof the liquid crystal panel 200 b is carried out similarly to theoperation in the first embodiment.

(B) Summary

As above, the liquid crystal panel 200 b of the present embodiment isbased on the FFS system, and image displaying is carried out throughapplication of a lateral electric field to the liquid crystal layer 203.Furthermore, as described above, the operation of detection of the touchposition is carried out similarly to the operation in the firstembodiment.

In the present embodiment, a slit KK is formed in the surface of adetecting electrode 24 opposed to the counter electrode 23 b. Thus,similarly to the first embodiment, the detection sensitivity of thetouch sensor TS can be enhanced, and detection of the touch position ofa sensing object can be carried out with high accuracy.

Therefore, the present embodiment can carry out the detection of thetouch position of a sensing object with high accuracy.

The same configuration can be employed for, besides the FFS system,another mode in which a lateral electric field is applied to the liquidcrystal layer 203, such as the in-plane-switching (IPS) system. Also inthis case, the same advantages can be achieved.

3. Third Embodiment

A third embodiment of the present invention will be described below.

FIG. 17 is a diagram showing the outline of the configuration of adisplay device 100 c in the third embodiment of the present invention.

As shown in FIG. 17, in the display device 100 c of the presentembodiment, a liquid crystal panel 200 c is different from the liquidcrystal panel 200 in the first embodiment. Furthermore, a touch panel209 is further disposed over the liquid crystal panel 200 c. Except forthese points and points relating thereto, the third embodiment is thesame as the first embodiment. Therefore, description of the overlappingpart is omitted.

(A) Configuration of Liquid Crystal Panel

The configuration of the liquid crystal panel 200 c will be described.

FIG. 18 is a diagram showing the configuration of the liquid crystalpanel 200 c in the third embodiment of the present invention. FIG. 18 isa sectional view schematically showing the outline of pixels P.

As shown in FIG. 18, the touch sensors TS are not provided in the liquidcrystal panel 200 c differently from the first embodiment.

Therefore, the detecting electrodes 24 (see FIG. 3) included in thetouch sensors TS are not provided over the counter substrate 202included in the liquid crystal panel 200 c.

Furthermore, a counter electrode 23 c is not formed as plural electrodesseparated from each other differently from the first embodiment.Although not shown in the diagram, in the present embodiment, thecounter electrode 23 c is formed in a blanket film manner on aplanarizing film 22 in such a manner as to monolithically cover theentire surface of a display area PA in which plural pixel electrodes 62p are arranged. In image displaying, a common potential Vcom is appliedto the counter electrode 23 c.

(B) Configuration of Touch Panel

The configuration of the touch panel 209 will be described.

FIG. 19 is a diagram showing the configuration of the touch panel 209 inthe third embodiment of the present invention. FIG. 19 schematicallyshows a section of the touch panel 209.

As shown in FIG. 19, the touch panel 209 includes a touch panelsubstrate 209 s.

In the touch panel 209, the touch panel substrate 209 s is a substratecomposed of an optically-transparent insulator and is formed of e.g.glass. In the touch panel substrate 209 s, touch sensors TS are providedas shown in FIG. 19.

The touch sensor TS is provided by sandwiching of the touch panelsubstrate 209 s as a dielectric substance by a counter electrode 23 tand a detecting electrode 24 t as shown in FIG. 19, and forms thecapacitive touch panel 209. That is, the touch sensor TS is soconfigured that the electrostatic capacitance changes when a sensingobject (not shown) is brought close to the detecting electrode 24 t.

In the touch sensor TS, the counter electrode 23 t is formed on thelower surface of the touch panel substrate 209 s as shown in FIG. 19.The counter electrode 23 t is a transparent electrode that transmitsvisible light and is formed by using e.g. ITO similarly to the firstembodiment.

FIG. 20 is a diagram showing the detailed configuration of the counterelectrodes 23 t in the third embodiment of the present invention. FIG.20 is a top view of the counter electrodes 23 t.

As shown in FIG. 20, the counter electrodes 23 t are in a stripe mannerand extend along the horizontal direction x on the surface of the touchpanel substrate 209 s similarly to the first embodiment. Furthermore,the counter electrodes 23 t are so disposed that plural electrodes arearranged at intervals in the vertical direction y. Specifically, nelectrodes, i.e. first to n-th counter electrodes 23 t 1 to 23 t n, areprovided as the counter electrodes 23 t in the direction from the upperside toward the lower side.

Each of the first to n-th counter electrodes 23 t_1 to 23 t_n iselectrically connected to a sensor driver S as shown in FIG. 20 and issequentially selected to be supplied with a drive signal Sg output fromthe sensor driver S, similarly to the first embodiment. That is, each ofthe first to n-th counter electrodes 23 t_1 to 23 t_n is supplied withthe drive signal Sg based on line-sequential scan driving. Similarly tothe first embodiment, the drive signal Sg having the common potentialVcom is supplied.

In the touch sensor TS, the detecting electrode 24 t is formed on theupper surface of the touch panel substrate 209 s as shown in FIG. 19.The detecting electrode 24 t is a transparent electrode that transmitsvisible light and is formed by using e.g. ITO.

FIG. 21 is a diagram showing the detailed configuration of the detectingelectrodes 24 t in the third embodiment of the present invention. FIG.21 is a top view of the detecting electrodes 24 t.

As shown in FIG. 21, the detecting electrodes 24 t are in a stripemanner and extend along the vertical direction y on the surface of thetouch panel substrate 209 s similarly to the first embodiment.Furthermore, the detecting electrodes 24 t are so disposed that pluralelectrodes are arranged at intervals in the horizontal direction x.Specifically, k electrodes, i.e. first to k-th detecting electrodes 24t_1 to 24 t_k, are provided as the detecting electrodes 24 t in thedirection from the left side toward the right side.

Each of the first to k-th detecting electrodes 24 t_1 to 24 t_k iselectrically connected to a detector DET as shown in FIG. 21, andoutputs a detection signal Vdet to the detector DET.

Furthermore, as shown in FIG. 21, slits KK are formed in the surface ofeach of the detecting electrodes 24 t opposed to the counter electrodes23 t similarly to the first embodiment. The slits KK extend along thevertical direction y inside each detecting electrode 24 t and are soprovided that plural slits are arranged at intervals in the horizontaldirection x.

In the touch panel 209 of the present embodiment, the touch sensors TSare driven and the touch position is detected similarly to the firstembodiment.

Specifically, some of the plural counter electrodes 23 t are selectedand supplied with the drive signal Sg. Furthermore, the counterelectrodes 23 t as the selected electrodes are shifted in the verticaldirection y and the drive signal Sg is supplied similarly. Thisoperation is repeatedly carried out, so that the touch position isdetected.

(C) Summary

As above, in the touch panel 209 of the present embodiment, theoperation of detection of the touch position is carried out similarly tothe first embodiment as described above.

In the present embodiment, the slits KK are formed in the surface of thedetecting electrode 24 t opposed to the counter electrode 23 t. Thus,similarly to the first embodiment, the detection sensitivity of thetouch sensor TS can be enhanced, and the touch position of a sensingobject can be detected with high accuracy.

Consequently, the present embodiment can carry out the detection of thetouch position of the sensing object with high accuracy.

4. Fourth Embodiment

A fourth embodiment of the present invention will be described below.

FIG. 22 is a diagram showing the detailed configuration of detectingelectrodes 24 d in the fourth embodiment of the present invention. FIG.22 is a top view of the detecting electrodes 24 d.

As shown in FIG. 22, the detecting electrodes 24 d in the presentembodiment are different from the detecting electrodes 24 in the firstembodiment. Except for this point and points relating thereto, thefourth embodiment is the same as the first embodiment. Therefore,description of the overlapping part is omitted.

(A) Detecting Electrode

As shown in FIG. 22, the detecting electrodes 24 d are in a stripemanner and extend along the vertical direction y. Furthermore, thedetecting electrodes 24 d are so disposed that plural electrodes arearranged at intervals in the horizontal direction x. Specifically, kelectrodes, i.e. first to k-th detecting electrodes 24 d_1 to 24 d_k,are provided as the detecting electrodes 24 d in the direction from theleft side toward the right side.

In the detecting electrodes 24 d, slits KK are formed. The slits KKextend along the vertical direction y inside each detecting electrode 24d and are so provided that plural slits are arranged at intervals in thevertical direction y and the horizontal direction x. That is, the slitsKK having a rectangular shape are formed in a lattice manner.

(B) Summary

As above, in the present embodiment, the slits KK having a rectangularshape are formed in a lattice manner in the detecting electrodes 24 d insuch a way that beams intersect with each other inside the detectingelectrodes 24 d. This can prevent the occurrence of breaking in thedetecting electrodes 24 d. In particular, even if a pattern processingdefect occurs in the manufacturing, the occurrence of breaking can beprevented because many connected parts exist inside the detectingelectrode 24 d.

5. Fifth Embodiment

A fifth embodiment of the present invention will be described below.

FIG. 23 is a diagram showing the detailed configuration of detectingelectrodes 24 e in the fifth embodiment of the present invention. FIG.23 is a top view of the detecting electrodes 24 e.

As shown in FIG. 23, the detecting electrodes 24 e in the presentembodiment are different from the detecting electrodes 24 in the firstembodiment. Except for this point and points relating thereto, the fifthembodiment is the same as the first embodiment. Therefore, descriptionof the overlapping part is omitted.

(A) Detecting Electrode

As shown in FIG. 23, the detecting electrodes 24 e are in a stripemanner and extend along the vertical direction y. Furthermore, thedetecting electrodes 24 e are so disposed that plural electrodes arearranged at intervals in the horizontal direction x. Specifically, kelectrodes, i.e. first to k-th detecting electrodes 24 e_1 to 24 e_k,are provided as the detecting electrodes 24 e in the direction from theleft side toward the right side.

In the detecting electrodes 24 e, slits KK are formed. The slits KK areformed into a circular shape inside each detecting electrode 24 e andare so provided that plural slits are arranged at intervals in thevertical direction y and the horizontal direction x.

(B) Summary

As above, in the present embodiment, the slits KK having a circularshape are formed in the detecting electrodes 24 e. Thus, the fringeelectric field is generated more uniformly between the detectingelectrodes 24 e and the scanning electrodes.

Therefore, the present embodiment can carry out detection of the touchposition of a sensing object with high accuracy.

The slits KK may be formed into any of various shapes besides theabove-described shapes.

FIG. 24 is a diagram showing the detailed configuration of detectingelectrodes in modification examples of the embodiments of the presentinvention. FIG. 24 is a top view of the detecting electrodes.

As shown in FIG. 24A, slits KK having a rectangular shape may be soformed that the ends thereof in the vertical direction y are atpositions different from each other in the horizontal direction x.

As shown in FIG. 24B, slits KK having a hexagonal shape may be soprovided as to be arranged in a honeycomb manner.

Furthermore, as shown in FIG. 24C, slits KK having an equilateraltriangular shape may be so disposed that the slits KK are alternatelyturned upside down in the horizontal direction x and the groups of theslits KK are alternately symmetric with each other in the verticaldirection y.

Moreover, as shown in FIG. 24D, slits KK having a rhombic shape may beso formed as to be disposed along the vertical direction y and thehorizontal direction x.

6. Others

The mode for carrying out the present invention is not limited to theabove-described embodiments, but various modified modes, such ascombination of features of the respective embodiments, can be employed.

In the driving of the touch sensor in the above-described embodiments,the operation of AC-driving the counter electrodes is repeatedly carriedout with the shift in the vertical direction, in which the plural (n)counter electrodes are arranged. In this AC-driving operation,consecutive plural (m (m<n)) counter electrodes are selected andsimultaneously AC-driven. In this operation, the plural (m (m<n))counter electrodes are so selected as to include the counter electrodesused in the pixel driving operation. Furthermore, in consecutiveAC-driving operation, the above-described shift is so carried out thatat least one counter electrode is continuously AC-driven. However, thedriving of the touch sensor is not limited to this operation. Forexample, the above-described operation of AC-driving may be carried outfor each counter electrode one by one.

In the above-described embodiments, the touch sensor is formed in thedisplay area of the liquid crystal panel. However, the configuration isnot limited thereto but the embodiments may be applied to aconfiguration in which the touch sensor is formed in the peripheral areaof the liquid crystal panel.

In the above-described embodiments, the liquid crystal panel is atransmissive panel. However, the configuration is not limited theretobut the embodiments may be applied to a configuration in which theliquid crystal panel is a reflective panel or a semi-transmissive panelthat allows use of both a transmissive type and a reflective type.

Furthermore, the embodiments of the present invention may be applied toa display panel other than the liquid crystal panel, such as an organicEL display.

The display device 100 and so on of the embodiments can be used as aunit in various kinds of electronic apparatus.

FIGS. 25 to 29 are diagrams showing electronic apparatus to which thedisplay device 100 according to the embodiment of the present inventionis applied.

As shown in FIG. 25, in television apparatus for receiving anddisplaying television broadcasting, the display device 100 can be usedas a display device that displays the received images on the displayscreen and accepts operation commands by the operator.

Furthermore, as shown in FIG. 26, in a digital still camera, the displaydevice 100 can be used as a display device that displays images such asimages captured by the camera on the display screen and acceptsoperation commands by the operator.

In addition, as shown in FIG. 27, in a notebook personal computer, thedisplay device 100 can be used as a display device that displaysoperation images and so forth on the display screen and acceptsoperation commands by the operator.

Moreover, as shown in FIG. 28, in a cellular phone terminal, the displaydevice 100 can be used as a display device that displays operationimages and so forth on the display screen and accepts operation commandsby the operator.

Furthermore, as shown in FIG. 29, in a video camcorder, the displaydevice 100 can be used as a display device that displays operationimages and so forth on the display screen and accepts operation commandsby the operator.

In the above-described embodiments, the counter electrodes 23, 23 b, 23c, and 23 t are equivalent to the scanning electrode and the commonelectrode set forth in the claims. In the above-described embodiments,the detecting electrodes 24, 24 t, 24 d, and 24 e are equivalent to thedetecting electrode set forth in the claims. In the above-describedembodiments, the pixel electrodes 62 p and 62 pb are equivalent to thepixel electrode set forth in the claims. In the above-describedembodiments, the display devices 100 and 100 c are equivalent to thedisplay device and the information input device set forth in the claims.In the above-described embodiments, the liquid crystal panels 200, 200b, and 200 c are equivalent to the display panel and the touch panel setforth in the claims. In the above-described embodiments, the TFT arraysubstrate 201 is equivalent to the first substrate set forth in theclaims. In the above-described embodiments, the counter substrate 202 isequivalent to the second substrate set forth in the claims. In theabove-described embodiments, the liquid crystal layer 203 is equivalentto the liquid crystal layer set forth in the claims. In theabove-described embodiment, the touch panel 209 is equivalent to thetouch panel set forth in the claims. In the above-described embodiments,the slit KK is equivalent to the slit set forth in the claims. In theabove-described embodiments, the touch sensor TS is equivalent to thetouch sensor set forth in the claims.

The present application contains subject matter related to thatdisclosed in Japanese Priority Patent Application JP 2009-102319 filedin the Japan Patent Office on Apr. 20, 2009, the entire content of whichis hereby incorporated by reference.

What is claimed is:
 1. An information input device comprising: aplurality of scanning electrodes extending along a first direction; aplurality of detecting electrodes opposing the scanning electrodes andextending along a second direction crossing the first direction; and adielectric substance between the scanning electrodes and the detectingelectrodes, wherein, each of the detecting electrodes includes aplurality of slits formed in a portion of the detecting electrodeoverlapping the scanning electrodes, and each of the slits has atriangular shape and is inverted relative to an adjacent slit in thefirst direction.
 2. The information input device according to claim 1,wherein each of the slits has an equilateral triangular shape.
 3. Theinformation input device according to claim 1, wherein a portion of eachdetecting electrode not overlapping the scanning electrodes protrudes inthe second direction.
 4. The information input device according to claim1, wherein each of the slits is inverted relative to the adjacent slitin the second direction.
 5. The information input device according toclaim 1, wherein each of the detecting electrodes is a transparentelectrode that transmits visible light.
 6. The information input deviceaccording to claim 1, wherein each of the detecting electrodes has aside extending along a direction different from the first and seconddirections.
 7. A display device comprising a display panel having atouch sensor that detects a position to which a sensing object is inproximity with respect to a display surface, the touch sensor including:a plurality of scanning electrodes extending along a first direction; aplurality of detecting electrodes opposing the scanning electrodes andextending along a second direction crossing the first direction; and adielectric substance between the scanning electrodes and the detectingelectrodes, wherein, each of the detecting electrodes includes aplurality of slits formed in a portion of the detecting electrodeoverlapping the scanning electrodes, and each of the slits has atriangular shape and is inverted relative to an adjacent slit in thefirst direction.
 8. The display device according to claim 7, whereineach of the slits has an equilateral triangular shape.
 9. The displaydevice according to claim 7, wherein a portion of each detectingelectrode not overlapping the scanning electrodes protrudes in thesecond direction.
 10. The display device according to claim 7, whereineach of the slits is inverted relative to the adjacent slit in thesecond direction.
 11. The display device according to claim 7, whereineach of the detecting electrodes is a transparent electrode thattransmits visible light.
 12. The display device according to claim 7,wherein each of the detecting electrodes has a side extending along adirection different from the first and second directions.
 13. Thedisplay device according to claim 7, wherein the display panel is aliquid crystal panel that includes a first substrate, a second substrateopposing the first substrate, and a liquid crystal layer providedbetween the first substrate and the second substrate.
 14. The displaydevice according to claim 7, wherein: the detecting electrodes areprovided on a surface of the first substrate on an opposite side to asurface of the first substrate opposing the second substrate; and thescanning electrodes are provided between the first substrate and thesecond substrate in such a manner as to be opposed to the detectingelectrodes with the first substrate between the detecting electrodes andthe scanning electrodes.
 15. The display device according to claim 7,wherein: the display panel includes (a) a plurality of pixel electrodesarranged in a display area, and (b) a common electrode provided at aninterval from the pixel electrodes in the display area; and the scanningelectrodes are used as the common electrode.
 16. A display devicecomprising a display panel having a touch sensor that detects a positionto which a sensing object is in proximity with respect to a displaysurface, the touch sensor including: a plurality of scanning electrodesextending along a first direction; a plurality of detecting electrodesopposing the display surface and extending along a second directioncrossing the first direction; and wherein, each of the detectingelectrodes includes a plurality of slits formed in a portion of thedetecting electrode overlapping the scanning electrodes, and each of theslits has a triangular shape and is inverted relative to an adjacentslit in the second direction.
 17. The display device according to claim16, wherein each of the slits has an equilateral triangular shape. 18.The display device according to claim 16, wherein a portion of eachdetecting electrode not overlapping the scanning electrodes protrudes inthe second direction.
 19. The display device according to claim 16,wherein each of the slits is inverted relative to the adjacent slit inthe first direction.